1. Field of the Invention
The present invention relates to a vehicle air conditioning system, and more particularly to a vehicle air conditioning system having an additional branch duct such as an upper ventilation duct or a rear ventilation duct.
2. Description of the Related Art
Generally, in a vehicle air conditioning system, air-conditioned air generated in an air conditioning unit (heating and cooling unit) is forced to flow out of unit openings, such as a ventilation opening, defroster opening, or footwell opening, and conducted to outlets, such as a ventilation outlet, defroster outlet, or footwell outlet. Japanese Patent Application Laid-Open No. H6(1994)-92135 discloses a vehicle air conditioning system which has a rear ventilation duct branching off from a ventilation duct to conduct air to a rear ventilation outlet.